In general, a fuel cell has a poor actuation property as compared with another power source. A power generation efficiency of such a fuel cell decreases owing to lowering of a temperature and poisoning of an electrode catalyst, and there occurs a case where a desired voltage/current cannot be supplied so that an apparatus (a motor or the like) cannot be actuated.
In view of such a situation, a method is suggested in which at least one of an anode fuel (e.g., a fuel gas) and a cathode fuel (e.g., an oxidizing gas) to be supplied to electrodes is brought into a shortage state, and an overvoltage of a part of the electrodes is increased to raise the temperature of the fuel cell, whereby the poisoned electrode catalyst is recovered and the fuel cell is warmed up (e.g., see Patent Document 1 described below).    [Patent Document 1] Japanese Patent Publication No. 2003-504807